120721644 has 24 divisors (see below), whose sum is σ = 312982320. Its totient is φ = 40240512.

The previous prime is 120721637. The next prime is 120721673. The reversal of 120721644 is 446127021.

120721644 is a `hidden beast` number, since 12 + 0 + 7 + 2 + 1 + 644 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 558789 + ... + 559004.

It is an arithmetic number, because the mean of its divisors is an integer number (13040930).

Almost surely, 2^120721644 is an apocalyptic number.

It is an amenable number.

120721644 is an abundant number, since it is smaller than the sum of its proper divisors (192260676).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

120721644 is a wasteful number, since it uses less digits than its factorization.

120721644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1117806 (or 1117798 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 120721644 is about 10987.3401694860. The cubic root of 120721644 is about 494.2291767750.

Adding to 120721644 its reverse (446127021), we get a palindrome (566848665).

The spelling of 120721644 in words is "one hundred twenty million, seven hundred twenty-one thousand, six hundred forty-four".